1. Field of the Invention
The present invention relates to connectors for sealing tubing to a device and, in particular, to connectors in which the integrity of the sealing can be tested.
2. Description of the Related Art
In the hydrocarbon recovery arts, boreholes penetrating the earth are used for production of hydrocarbons. Many types of components may be disposed in the boreholes for the production of the hydrocarbons. Some of the components require connectors to connect one component to another component. For example, tubing containing a fluid may be connected to a valve used to control the flow of the fluid. A connector is used to connect the tubing to the valve.
The borehole can present a very harsh environment to the components disposed in the borehole. In many cases, the borehole is filled with a fluid at a high pressure and a high temperature. In addition, the fluid can have properties that can damage internal parts of the components. If the connector fails by having leaking connections, the internal parts of the connected components can be exposed to the harsh environment and be damaged. Damaged components in turn can be very costly both in terms of repair and in lost production.
Historically, downhole connections of fluid carrying tubing were pressure tested using connectors having a parting piston to contain pressure between the connections. Once the test is completed, additional pressure must be applied to break (i.e., part) the piston to allow the fluid to flow through the valve.
Unfortunately, there are a number of issues that can negatively impact the parting of the piston. These issues include machining tolerances on the parting diameter as well as sealing surfaces, variations in material properties, effectiveness of seals, and fluid trapped “behind” the piston. Any of these issues can result in the piston parting early (i.e., parting before the test is complete), requiring excessive overpressure that can potentially damage components, failure to complete the test, or failure to part the piston. Even after successful parting, there is a chance that debris from the piston or one of the seals could flow into a backcheck section of the valve and lodge in an area, which prevents a check dart from either opening or closing.
Therefore, what are needed are techniques for testing the integrity of seals made up in a connector connecting tubing to a device.